Gas delivery systems for semiconductor processing chambers utilize flow splitting methods to improve mix ratio accuracy, repeatability, and reproducibility in multi-injection point or shared chamber architectures. Flow splitting can reduce costs of a gas delivery system significantly in a number of applications. The flow ratio controller (FRC) can be an effective flow splitting device, but is generally very complex.
FRCs are widely used in semiconductor industries to distribute gas or gas mixtures to different zones in a process chamber. However, FRCs often utilize algorithms that create a non-symmetric condition in order to achieve desired new setpoints in the fastest way possible at the expense of symmetric transient flow. Additionally, FRCs are often limited in number of channels and flow range, preventing scalability without incurring high costs. Further, control architecture is contained within the device, limiting the device to point of use control.